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Thermacell Patio Shield vs Radius (2021): Which Mosquito Repellent Should You Get?

Traditional mosquito repellents typically use DEET. While effective, the ingredient has plenty of drawbacks, including an unpleasant smell and the potential to cause skin irritations. In addition, sustained protection in larger spaces and environs can be difficult. Thermacell tries to remedy this with area repellants.

Its Thermacell Patio Shield series and Thermacell Radius, for instance, can create a zone of protection up to 15-feet in radius. Although their mechanism of action is the same, there are key differences between them, like the active ingredient used and their power type. To know which one you should get, we’ve compared the two below.

Thermacell Patio Shield vs Radius Comparison Chart

ModelThermacell Patio Shield Mosquito RepellerThermacell Radius Zone Mosquito Repellent, Gen 2.0
 Amazon productAmazon product
PriceAmazon productAmazon product
TypeArea repellantArea repellant
Active IngredientD-cis/trans allethrinMetofluthrin
Protection Radius15 ft.15 ft.
PowerFuel cartridgeRechargeable battery
Battery Lifen/a6.5 hours
Fuel Duration12 hoursn/a
Refill Mat Duration4 hours to 12 hours, depending on mat12 to 40 hours, depending on mat
TSA CompliantNoYes
Dimensions3.4 x 3.4 x 6.5 in.3.1 x 1.9 x 3.3 in.
Weight0.6 lb0.4 lb
WarrantyOne yearTwo years

Catalog and Technology

The Thermacell Patio Shield is a fuel-powered repellent that uses allethrin. Meanwhile, the Thermacell Radius is battery-powered and employs metofluthrin.

Thermacell Patio Shield vs Radius How They Work
Here’s a look at how the Thermacell Patio Shield (left) and Radius (right) work.

Thermacell has a broad catalog of mosquito repellents. The Patio Shield series itself includes seven models. If you want a premium look, you can opt for the Metal Edition. For those who want protection as well as lighting, there’s the Thermacell Patio Shield Torch and Lantern. The latter features a lantern design with a handle for improved portability. Most users, however, will probably be happy with the standard Patio Shield.

Meanwhile, the Radius is one of two battery-powered area repellents from the brand β€” the other being the E55. If you’d like to see how they compare, you can check out our Thermacell E55 vs Radius review. Meanwhile, the Patio Shield uses fuel cartridges. While the power source is different, the tech behind these devices is largely the same.

On both devices, you simply insert a mat that contains the repellent ingredient. Using either battery or fuel, the Thermacell Patio Shield and Radius will generate heat to activate the ingredient. It’s then emitted across a large zone of protection as a spatial repellent.

The Patio Shield uses the active ingredient allethrin, which requires butane heat to vaporize, hence the fuel cartridge. The Radius, on the other hand, employs metofluthrin, which evaporates more readily. Both ingredients are synthetic versions of a compound found in the chrysanthemum flower. Studies have shown allethrin and metofluthrin are effective at repelling mosquitoes.


The Thermacell Radius is a sleeker and more compact device than the Patio Shield.

Thermacell Patio Shield vs Radius Design Comparison
What’s in the box? Here are the items you get when you buy a Thermacell Patio Shield or Radius.

What’s great about Thermacell products is that they don’t look like repellents. From afar, it’s easy to mistake the Patio Shield as an oversized tumbler. The Radius, on the other hand, looks more like a special container. Next to each other, the Patio Shield towers over the Radius, partly because the repellent’s body has to accommodate the fuel cartridge. If you get the Radius, you’ll benefit from a sleeker and more compact repellent.

There are also a couple of differences in their hardware and operating components. For instance, the Thermacell Patio Shield is open at the base. This is where you thread the fuel cartridge into the repellent. Repellent mats, on the other hand, are inserted into the top. To start the device, you rotate the base to On. A view window on top of the device should show a yellow or blue glow to indicate the repellent is working.

With the Thermacell Radius, starting the repellent is a lot more user-friendly. You simply open the device and insert the heat-activated repellent refill. Once you put the lid back on, you can start the Radius via a power button. A ring light surrounds the button to show the status of the device. Nearer the base, you’ll find a battery indicator, too.

Now, homeowners can get the Patio Shield in seven different colors. As mentioned in the Catalog section, there’s also a brushed metal edition. In contrast, the Radius is only available in two colors β€” black and blue.

Performance and Battery Life

Thermacell’s Radius may have a shorter runtime on battery than the Patio Shield does on fuel, but the former can still be used while charging.

Thermacell Patio Shield vs Radius Performance Review
The 15-feet protection zone offered by the Thermacell repellants works in any outdoor setting.

Despite their difference in size, both the Patio Shield and Radius deliver the same zone of protection. Thermacell claims these repellents offer 15-feet coverage. Because they operate wirelessly, you can also bring and use the devices in any indoor or outdoor setting. It’s important to note that, unlike the Radius, the Patio Shield isn’t TSA-compliant, so you cannot bring it with you on flights.

In terms of runtime, the Thermacell Patio Shield’s fuel cartridge is rated to last 12 hours. The battery-powered Radius, on the other hand, can only operate for up to 6.5 hours. Charge time also takes 5 hours. However, you can still use the Radius while Charging, which makes its potential runtime much longer than the Patio Shield.

Refill Mats

Thermacell’s Radius has longer-lasting refill mats than the Thermacell Patio Shield.

Thermacell Patio Shield vs Radius Refills
On the left, Thermacell fuel cartridge refills for the Patio Shield; on the right, refill mats for the Radius.

At the heart of Thermacell’s repellants are its refills. For the Patio Shield, you can get the fuel cartridge refills and the mats. As mentioned in the performance, fuel cartridges typically last 12 hours. You can also get them in 4-packs and 12-packs.

The refill mats, on the other hand, can last anywhere from 4 hours to 12 hours. The original variant of a Patio Shield refill, for instance, lasts up to 4 hours and usually comes in packs of 3, 12, 30, or 75 mats. If you want longer-lasting protection, you can get the more expensive Max Life refill that lasts 12 hours per mat.

Out of the box, the Thermacell Radius includes a 12-hour refill. Once you’ve used it up, you do have options for longer-lasting mats. For instance, there’s a 36-hour repellent refill sold individually. The other option β€” a pack of 3 refills β€” lasts 40 hours each.


The Thermacell Radius is a more cost-effective purchase but there may be some instances where the Patio Shield is more convenient.

Amazon product

A look at the specs and features shows the Thermacell Patio Shield is quite comparable with the Thermacell Radius when it comes to the protection zone. However, the battery-powered repellent has some advantages. The Radius, for instance, is more compact than its fuel-powered counterpart. Even if it has a shorter runtime, it can still operate while being charged. Plus, you don’t have to stock up on fuel cartridges.

That being said, there are instances where the Patio Shield might be more convenient. If you’re camping, for instance, where there’s no nearby power outlet, the Patio Shield can be a lifesaver. Even at backyard parties, it’s probably less of a hassle if you’re not worrying about having to recharge a repellant. Of course, there are simple solutions like extension cords. But it’s worth thinking about these instances when deciding which Thermacell insect repellent you should get.


πŸ“Œ What’s the difference between the Thermacell Patio Shield and Radius?

The Thermacell Patio Shield is an area repellent powered by fuel cartridges. It also uses refill mats with allethrin as the active ingredient. Meanwhile, the Thermacell Radius is a battery-powered repellent. Instead of allethrin, the Radius uses mats with the active ingredient metofluthrin.

πŸ“Œ Is the Thermacell Patio Shield worth it?

Based on our Thermacell Patio Shield review, the device is worth it. If you want to protect a large area from mosquitoes, the repellent works reliably. Its fuel cartridge can also last up to 12 hours.

πŸ“Œ How long is the warranty on the Thermacell Radius?

The Thermacell Radius carries a two-year warranty, which can be extended to three with registration.

πŸ“Œ Is the Thermacell Radius safe to use?

The US Environmental Protection Agency (EPA) has approved the use of metofluthrin in repellent devices. If used as directed, the Thermacell Radius is safe to use. The refill mats of the device are also scent-free and DEET-free.

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Mari Bassig

Senior Editor, writer and researcher passionate about gadgets, social media, and music.